Walk-in bathtubs comprise high tub walls with a high built in seat and a side door, allowing the user to walk into the tub from the side and sit down without having to climb down into a low bath tub. FIG. 1 shows a typical example of a walk-in bathtub in accordance with the prior art. Walk-in tubs are particularly suited for individuals who have physical limitations that make it difficult or dangerous to climb into and out of a regular, low bathtub or to stand up in a shower for extended periods of time. Such limitations might include physical disabilities or simply the reduced strength, balance and range of motion that typically occur with advancing age. Walk-in tubs are not only easier to enter and exit than conventional bathtubs they also reduce the chances of slips and falls compared to conventional tubs and showers.
In addition to safety, the ease of entering the tub via the side walk-in door also provides users with independence, allowing them to bathe without the assistance of another person when getting into and out of the tub.
Of central importance for walk-in tubs is the design of side door itself. Specifically, the position and swing path of the door affects the operation of the tub and its ease of use. Prior art designs like the one shown in FIG. 1, in which the side door opens to the outside of the tub, have to maintain a proper seal against the outward pressure of the water when the tub is filled. By and large, this task is left up to the locking handle used to close and secure the door. Adding to the difficulty in maintaining a proper seal is the fact that most walk-in tubs do not have a door frame. Instead, the door is merely bolted directly onto the wall of the tub. Depending on the depth of the tub and the materials used in it construction, the perimeter of the door threshold (in the absence of a frame) can buckle and distort under the pressure of the water, leading to potential leaks.
FIG. 2 shows an improved prior art design that overcomes many of the problems noted above. In this design, the side door 201 opens to the inside of the tub. Therefore when the door is closed and the bath is filled, the water pushes against the door in the direction of the closed position, thereby enhancing the strength of the water seal instead of working against it. Also present in this design is a door frame 202 onto which the door 201 is mounted. The frame prevents buckling and warping around the perimeter of the door threshold, thereby preventing leaks in the water seal due to buckling from water pressure against the walls of the tub.
However, despite the advantages of the improved door design shown in FIG. 2, it creates a new problem of its own. As can be seen in the figure, because the door 201 opens inward, it has to swing across the foot well of the tub. If a person is standing or sitting in the tub, the legs have to be moved out of the door's path during opening and closing. While this may seem like a trivial inconvenience, one must keep in mind that most users of walk-in tubs have some degree of movement impairment. Depending on the size of the foot well of the tub, the size and length of the user's legs and the degree of impairment, the user may have a great deal of difficulty opening and closing the door while inside the tub.
Therefore it would be desirable to have a door design that that opens to the inside of the walk-in tub but does not swing through the foot well of the tub, thereby avoiding interference with the user's legs.